Abstract

The synthesis of arbitrarily shaped femtosecond pulses with 100 fs features is traditionally accomplished by linear spectral filtering in a nondispersive grating/lens system in which a spatial mask modifies the amplitudes and/or phases of spatially dispersed frequency components.¹ However, the shaping of shorter pulses with significantly greater bandwidth is compromised by the presence of the lenses, which distort the pulses transmitted through the shaper by adding substantial cubic phase dispersion. Here we report on the extension of the pulse shaping technique to pulses 20 fs in duration and demonstrate shaped femtosecond pulses with 20 fs features using a modified shaping apparatus. For input pulses, we use 0.5 μJ, 20 fs pulses compressed using a novel pulse compression technique which utilizes the self-trapping of bright, two-dimensional spatial solitons in bulk nonlinear media.² The shaping apparatus consists of a pair of gratings placed at the outside focal planes a unit magnification, confocal pair of concave mirrors, which replace the achromatic lenses traditionally used in pulse shapers.¹ As an example, we demonstrate 10THz repetition rate pulse trains produced using phase-only filtering.

© 1991 Optical Society of America